Process for application of a metal layer on a substrate

ABSTRACT

The present invention relates to processes for application of a metal layer on a substrate via deposition of a metal from a metal salt solution by a chemical and/or electroplating method, a significant factor in these processes being that carbon nanotubes are present in the substrate surface. The present invention moreover relates to the use of carbon nanotubes for application of a metal layer on a substrate.

The present invention relates to processes for application of a metallayer on a substrate via deposition of a metal from a metal saltsolution, and also to the use of carbon nanotubes for application of ametal layer on a substrate.

Processes for metallizing materials which are usually electricallynon-conductive, such as plastics, are known. These metallized parts,such as metallized plastics parts, are used in a wide variety ofapplication sectors, and by way of example their electrical conductivitypermits their use as electrical components. They are moreover widelyused inter alia in the decorative sector, since while they have the sameappearance as articles manufactured entirely from metal they have lowerweight and can be produced at lower cost.

There are widely used processes for metallizing plastics wherecomparatively complicated pretreatment of the plastics surface is neededvia chemical or physical roughening or chemical or physical etchingprocesses, for example using chromic-sulfuric acid mixture, and/or withapplication of, for example, primer layers or adhesion-promoter layerscomprising noble metals, as a precondition for deposition of coherentand firmly adhering metal layers by a currentless and/or electroplatingmethod (see, for example, WO 01/77419).

Another known method for provision of plastics having electricalconductivity (this being a necessary precondition for metal depositionby an electroplating method) is incorporation of carbon nanotubes orcarbon nanofibrils into plastic. Examples of other advantages of theseelectrically conductive carbon nanotubes are that they have lower weightthan metal powders and that they usually give plastics increasedtoughness (see, for example, US 2006/0025515 A1).

DE 102 59 498 A1 discloses electrically conductive thermoplasticscomprising not only a particulate carbon compound, such as carbon blackor graphite, but also carbon nanofibrils. The plastics mixturesdescribed in that document have not only electrical conductivity butgood flowability, good surface quality, and also high toughness. Theyare particularly suitable for the electrostatic coating of plastics andfor improving the electrostatic properties of plastics. However, thesurface resistances disclosed in the specification are inadequate whenthe conductive thermoplastics are used as substrate in a process ofmetallizing by an electroplating method.

It is an object of the present invention to provide improved processesfor application of a metal layer on a substrate via deposition of ametal from a metal salt solution by a chemical and/or electroplatingmethod. Processes should in particular be made available in which metallayers can be deposited on a substrate with good adhesion to thesubstrate within comparatively short electroplating times, at low costand with good quality, and in which the metallized substrates havecomparatively low weight.

Accordingly, the processes mentioned in the introduction have been foundfor application of a metal layer on a substrate via deposition of ametal from a metal salt solution by a chemical and/or electroplatingmethod, a significant factor in these processes being that carbonnanotubes are present in the substrate surface.

The use of carbon nanotubes has moreover been found for application of ametal layer on a substrate.

The inventive processes permit improved application of a metal layer ona substrate via deposition of a metal from a metal salt solution by achemical and/or electroplating method. In particular, metal layers canbe deposited on a substrate by the inventive processes with goodadhesion to the substrate, within comparatively short electroplatingtimes, at low cost and with good quality. The metallized substrates thusproduced have comparatively low weight.

The inventive processes are described below, as are the other articles,processes, and uses.

A significant feature of the inventive processes is that carbonnanotubes are present in the substrate surface of the substrate to bemetallized. This means that either the substrate itself—and thereforealso its surface—comprises carbon nanotubes, or else that carbonnanotubes are applied in the form of an adherent polymer coating or of alacquer to a substrate in which no carbon nanotubes are intrinsicallypresent. The carbon nanotubes located in or on the substrate surfacebring about electrical conductivity, this being essential for thesubsequent process of metal deposition on the substrate by a chemicaland/or electroplating method. By way of example, there can be furtherelectrically conductive components, such as metal powders or carbonblack particles, located in or on the substrate surface alongside thecarbon nanotubes, in order to increase electrical conductivity, buttheir presence is not essential to the invention. The carbon nanotubesper se and their preparation are described (components B or B′) at alater stage below.

In preferred embodiments of the inventive processes, therefore, thesubstrates used in the process of metal deposition by a chemical and/orelectroplating method have been produced from a molding compositionwhich comprises carbon nanotubes and which is described in more detailat a later stage below. In other preferred embodiments of the inventiveprocesses, substrates used in the process of metal deposition by achemical and/or electroplating method are those which have been providedwith a dispersion described at a later stage below and comprising carbonnanotubes, and which have then been at least partially dried and/or atleast partially hardened.

Molding Compositions Comprising Carbon Nanotubes

In one preferred embodiment, the substrates that can be used in theinventive processes are based on thermoplastic molding compositionscomprising, based on the total weight of components A, B, C, and D,which is 100% by weight,

-   a from 20 to 99% by weight, preferably from 55 to 95% by weight,    particularly preferably from 60 to 92% by weight, of component A,-   b from 1 to 30% by weight, preferably from 5 to 25% by weight,    particularly preferably from 8 to 20% by weight, of component B.-   c from 0 to 10% by weight, preferably from 0 to 8% by weight,    particularly preferably from 0 to 5% by weight, of component C, and-   d from 0 to 40% by weight, preferably from 0 to 30% by weight,    particularly preferably from 0 to 10% by weight, of component D.

The individual components of these molding compositions are describedbelow:

Component A

In principle, any of the thermoplastic polymers is suitable as componentA. The thermoplastic polymers are generally those whose tensile strainat break is in the range from 10% to 1000%, preferably in the range from20 to 700, particularly preferably in the range from 50 to 500. (These,and all of the other, values for tensile strain at break and tensilestrength mentioned in this application are determined on test specimensof type 1BA (annex A of the standard mentioned: “small test specimens”)in the ISO 527-2:1996 tensile test.)

Examples of a suitable component A are polyethylene, polypropylene,polyvinyl chloride, polystyrene (impact-modified ornon-impact-modified), ABS (acrylonitrile-butadiene-styrene), ASA(acrylonitrile-styrene-acrylate), MABS (transparent ABS, comprisingmethacrylate units), styrene-butadiene block copolymer (e.g. Styroflex®or Styrolux® from BASF Aktiengesellschaft, K-Resin™ from CPC),polyamides, polyethylene terephthalate (PET), polyethylene terephthalateglycol (PETG), polybutylene terephthalate (PBT), aliphatic-aromaticcopolyesters (e.g. Exoflex® from BASF Aktiengesellschaft), polycarbonate(e.g. Makrolon® from Bayer AG), polymethyl methacrylate (PMMA),poly(ether) sulfones, and polyphenylene oxide (PPO).

As component A, preference is given to the use of one or more polymersselected from the group of impact-modified vinylaromatic copolymers, ofpolyolefins, of aliphatic-aromatic copolyesters, of polycarbonates, ofthermoplastic polyurethanes, and of styrene-based thermoplasticelastomers.

Polyamides can be used as likewise preferred component A.

Impact-Modified Vinylaromatic Copolymers:

Preferred impact-modified vinylaromatic copolymers are impact-modifiedcopolymers composed of vinylaromatic monomers and of vinyl cyanides(SAN). The preferred impact-modified SAN used preferably comprises ASApolymers and/or ABS polymers, or else(meth)acrylate-acrylonitrile-butadiene-styrene polymers (“MABS”,transparent ABS), or else blends of SAN, ABS, ASA, and MABS with otherthermoplastics, for example with polycarbonate, with polyamide, withpolyethylene terephthalate, with polybutylene terephthalate, with PVC,or with polyolefins.

The tensile strain at break values of the ASA and ABS that can be usedas components A are generally from 10% to 300%, preferably from 15 to250%, particularly preferably from 20% to 200%.

ASA polymers are generally impact-modified SAN polymers which compriseelastomeric graft copolymers of vinylaromatic compounds, in particularstyrene, and vinyl cyanides, in particular acrylonitrile, on polyalkylacrylate rubbers in a copolymer matrix composed, in particular, ofstyrene and/or α-methylstyrene and acrylonitrile.

In one preferred embodiment in which the thermoplastic moldingcompositions comprise ASA polymers, the elastomeric graft copolymerA^(R) of component A is composed of

-   a1 from 1 to 99% by weight, preferably from 55 to 80% by weight, in    particular from 55 to 65% by weight, of a particulate graft base A1    with a glass transition temperature below 0° C.,-   a2 from 1 to 99% by weight, preferably from 20 to 45% by weight, in    particular from 35 to 45% by weight, of a graft A2 composed of the    following monomers, based on A2,-   a21 from 40 to 100% by weight, preferably from 65 to 85% by weight,    of units of styrene, of a substituted styrene, or of a    (meth)acrylate, or of a mixture of these, in particular of styrene    and/or α-methylstyrene, as component A21, and-   a22 up to 60% by weight, preferably from 15 to 35% by weight, of    units of acrylonitrile or methacrylonitrile, in particular of    acrylonitrile, as component A22.

The graft A2 here is composed of at least one graft shell.

Component A1 Here is Composed of the Following Monomers

-   a11 from 80 to 99.99% by weight, preferably from 95 to 99.9% by    weight, of at least one C₁-C₈-alkyl acrylate, preferably n-butyl    acrylate and/or ethylhexyl acrylate, as component A 1,-   a12 from 0.01 to 20% by weight, preferably from 0.1 to 5.0% by    weight, of at least one polyfunctional crosslinking monomer,    preferably diallyl phthalate and/or DCPA, as component A12.

According to one embodiment of the invention, the average particle sizeof component A^(R) is from 50 to 1000 nm, with monomodal distribution.

In another embodiment, the particle size distribution of component A^(R)is bimodal, from 60 to 90% by weight having an average particle size offrom 50 to 200 nm, and from 10 to 40% by weight having an averageparticle size of from 50 to 400 nm, based on the total weight ofcomponent A^(R).

The average particle size and particle size distribution given are thesizes determined from the cumulative weight distribution. The averageparticle sizes are in all cases the weight average of the particlesizes. The determination of these is based on the method of W. Scholtanand H. Lange, Kolloid-Z. und Z.-Polymere 250 (1972), pp. 782-796, usingan analytical ultracentrifuge. The ultracentrifuge measurement gives thecumulative weight distribution of the particle diameter of a specimen.From this it is possible to deduce what percentage by weight of theparticles have a diameter identical to or smaller than a particularsize. The average particle diameter, which is also termed the d₅₀ of thecumulative weight distribution, is defined here as that particlediameter at which 50% by weight of the particles have a diameter smallerthan that corresponding to the d₅₀. Equally, 50% by weight of theparticles then have a larger diameter than the d₅₀. To describe thebreadth of the particle size distribution of the rubber particles, d₁₀and d₉₀ values given by the cumulative weight distribution are utilizedalongside the d₅₀ (average particle diameter). The d₁₀ and d₉₀ of thecumulative weight distribution are defined similarly to the d₅₀ with thedifference that they are based on, respectively, 10 and 90% by weight ofthe particles. The quotient

(d ₉₀ −d ₁₀)/d ₅₀ =Q

is a measure of the breadth of the particle size distribution.Elastomeric graft copolymers A^(R) preferably have Q values less than0.5, in particular less than 0.35.

The acrylate rubbers A1 are preferably alkyl acrylate rubbers composedof one or more C₁-C₈-alkyl acrylates, preferably C₄-C₈-alkyl acrylates,preferably with use of at least some butyl, hexyl, octyl or 2-ethylhexylacrylate, in particular n-butyl and 2-ethylhexyl acrylate. These alkylacrylate rubbers may comprise, as comonomers, up to 30% by weight ofhard-polymer-forming monomers, such as vinyl acetate,(meth)acrylonitrile, styrene, substituted styrene, methyl methacrylate,vinyl ether.

The acrylate rubbers also comprise from 0.01 to 20% by weight,preferably from 0.1 to 5% by weight, of crosslinking, polyfunctionalmonomers (crosslinking monomers). Examples of these are monomers whichcomprise two or more double bonds capable of copolymerization,preferably not 1,3-conjugated.

Examples of suitable crosslinking monomers are divinylbenzene, diallylmaleate, diallyl fumarate, diallyl phthalate, diethyl phthalate,triallyl cyanurate, triallyl isocyanurate, tricyclodecenyl acrylate,dihydrodicyclopentadienyl acrylate, triallyl phosphate, allyl acrylate,allyl methacrylate. Dicyclopentadienyl acrylate (DCPA) has proven to bea particularly suitable crosslinking monomer (cf. DE-C 12 60 135).

Component A^(R) is a graft copolymer. These graft copolymers A^(R) havean average particle size d₅₀ of from 50 to 1000 nm, preferably from 50to 800 nm, and particularly preferably from 50 to 600 nm. These particlesizes may be achieved if the graft base A1 used has a particle size offrom 50 to 800 nm, preferably from 50 to 500 nm, and particularlypreferably from 50 to 250 nm. The graft copolymer A^(R) generally hasone or more stages, i.e. is a polymer composed of a core and one or moreshells. The polymer is composed of a first stage (graft core) A1 and ofone or—preferably—more stages A2 (grafts) grafted onto this first stageand known as graft stages or graft shells.

Simple grafting or multiple stepwise grafting may be used to apply oneor more graft shells to the rubber particles, and each of these graftshells may have a different makeup. In addition to the graftingmonomers, polyfunctional crosslinking monomers or monomers comprisingreactive groups may also be included in the grafting process (see, forexample, EP-A 230 282, DE-B 36 01 419, EP-A 269 861).

In one preferred embodiment, component A^(R) is composed of a graftcopolymer built up in two or more stages, the graft stages generallybeing prepared from resin-forming monomers and having a glass transitiontemperature T_(g) above 30° C., preferably above 50° C. The structurehaving two or more stages serves, inter alia, to make the rubberparticles A^(R) (partially) compatible with the thermoplastic matrix.

An example of a preparation method for graft copolymers A^(R) isgrafting of at least one of the monomers A2 listed below onto at leastone of the graft bases or graft core materials A1 listed above.

In one embodiment of the invention, the graft base A1 is composed offrom 15 to 99% by weight of acrylate rubber, from 0.1 to 5% by weight ofcrosslinker, and from 0 to 49.9% by weight of one of the stated othermonomers or rubbers.

Suitable monomers for forming the graft A2 are styrene, α-methylstyrene,(meth)acrylates, acrylonitrile, and methacrylonitrile, in particularacrylonitrile.

In one embodiment of the invention, crosslinked acrylate polymers with aglass transition temperature below 0° C. serve as graft base A1. Thecrosslinked acrylate polymers are preferably to have a glass transitiontemperature below −20° C., in particular below −30° C.

In one preferred embodiment, the graft A2 is composed of at least onegraft shell, and the outermost graft shell of these has a glasstransition temperature of more than 30° C., while a polymer formed fromthe monomers of the graft A2 would have a glass transition temperatureof more than 80° C.

Suitable preparation processes for graft copolymers A^(R) are emulsion,solution, bulk, or suspension polymerization. The graft copolymers A^(R)are preferably prepared by free-radical emulsion polymerization in thepresence of latices of component A1 at from 20° C. to 90° C., usingwater-soluble or oil-soluble initiators, such as peroxodisulfate orbenzoyl peroxide, or with the aid of redox initiators. Redox initiatorsare also suitable for polymerization below 20° C.

Suitable emulsion polymerization processes are described in DE-A 28 26925, 31 49 358, and DE-C 12 60 135.

The graft shells are preferably built up in the emulsion polymerizationprocess described in DE-A 32 27 555, 31 49 357, 31 49 358, 34 14 118.The defined setting of the particle sizes of from 50 to 1000 nmpreferably takes place by the processes described in DE-C 12 60 135 andDE-A28 26 925, and Applied Polymer Science, volume 9 (1965), p. 2929.The use of polymers with different particle sizes is known from DE-A 2826 925 and U.S. Pat. No. 5,196,480, for example.

The process described in DE-C 12 60 135 begins by preparing the graftbase A1 by polymerizing in a manner known per se, at from 20 to 100° C.,preferably from 50 to 80° C., the acrylate(s) used in one embodiment ofthe invention and the polyfunctional crosslinking monomer, ifappropriate together with the other comonomers, in aqueous emulsion. Usemay be made of the usual emulsifiers, such as alkali metal alkyl- oralkylarylsulfonates, alkyl sulfates, fatty alcohol sulfonates, salts ofhigher fatty acids having from 10 to 30 carbon atoms or resin soaps. Itis preferable to use the sodium salts of alkylsulfonates or fatty acidshaving from 10 to 18 carbon atoms. In one embodiment, the amounts usedof the emulsifiers are from 0.5 to 5% by weight, in particular from 1 to2% by weight, based on the monomers used in preparing the graft base A1.Operations are generally carried out with a ratio of water to monomersof from 2:1 to 0.7:1 by weight. The polymerization initiators used arein particular the commonly used persulfates, such as potassiumpersulfate. However, it is also possible to use redox systems. Theamounts generally used of the initiators are from 0.1 to 1% by weight,based on the monomers used in preparing the graft base A1. Otherpolymerization auxiliaries which may be used during the polymerizationare the usual buffer substances which can set a preferred pH of from 6to 9, examples being sodium bicarbonate and sodium pyrophosphate, andalso from 0 to 3% by weight of a molecular weight regulator, such asmercaptans, terpinols or dimeric α-methylstyrene. The precisepolymerization conditions, in particular the nature, feed parameters,and amount of the emulsifier, are determined individually within theranges given above in such a way that the resultant latex of thecrosslinked acrylate polymer has a d₅₀ in the range from about 50 to 800nm, preferably from 50 to 500 nm, particularly preferably in the rangefrom 80 to 250 nm. The particle size distribution of the latex here ispreferably intended to be narrow.

In one embodiment of the invention, to prepare the graft polymer A^(R),in a following step, in the presence of the resultant latex of thecrosslinked acrylate polymer, a monomer mixture composed of styrene andacrylonitrile is then polymerized, and in one embodiment of theinvention here the weight ratio of styrene to acrylonitrile in themonomer mixture should be in the range from 100:0 to 40:60, andpreferably in the range from 65:35 to 85:15. This graft copolymerizationof styrene and acrylonitrile onto the crosslinked polyacrylate polymerserving as a graft base is again advantageously carried out in aqueousemulsion under the usual conditions described above. The graftcopolymerization may usefully take place in the system used for theemulsion polymerization to prepare the graft base A1, where furtheremulsifier and initiator may be added if necessary. The mixture ofstyrene and acrylonitrile monomers which is to be grafted on in oneembodiment of the invention may be added to the reaction mixture all atonce, in portions in more than one step, or preferably continuouslyduring the course of the polymerization. The graft copolymerization ofthe mixture of styrene and acrylonitrile in the presence of thecrosslinking acrylate polymer is carried out in such a way as to obtainin graft copolymer A^(R) a degree of grafting of from 1 to 99% byweight, preferably from 20 to 45% by weight, in particular from 35 to45% by weight, based on the total weight of component A^(R). Since thegrafting yield in the graft copolymerization is not 100%, the amount ofthe mixture of styrene and acrylonitrile monomers which has to be usedin the graft copolymerization is somewhat greater than that whichcorresponds to the desired degree of grafting. Control of the graftingyield in the graft copolymerization, and therefore of the degree ofgrafting of the finished graft copolymer A^(R), is a topic with whichthe person skilled in the art is familiar. It may be achieved, forexample, via the metering rate of the monomers or via addition ofregulators (Chauvel, Daniel, ACS Polymer Preprints 15 (1974), pp. 329ff.). The emulsion graft copolymerization generally gives approximately5 to 15% by weight, based on the graft copolymer, of free, ungraftedstyrene-acrylonitrile copolymer. The proportion of the graft copolymerA^(R) in the polymerization product obtained in the graftcopolymerization is determined by the method given above. Preparation ofthe graft copolymers A^(R) by the emulsion process also gives, besidesthe technical process advantages stated above, the possibility ofreproducible changes in particle sizes, for example by agglomerating theparticles at least to some extent to give larger particles. This impliesthat polymers with different particle sizes may also be present in thegraft copolymers A^(R). Component A^(R) composed of graft base and graftshell(s) can in particular be ideally adapted to the respectiveapplication, in particular with regard to particle size.

The graft copolymers A^(R) generally comprise from 1 to 99% by weight,preferably from 55 to 80% by weight, and particularly preferably from 55to 65% by weight, of graft base A1 and from 1 to 99% by weight,preferably from 20 to 45% by weight, particularly preferably from 35 to45% by weight, of the graft A2, based in each case on the entire graftcopolymer.

ABS polymers are generally understood to be impact-modified SAN polymersin which diene polymers, in particular poly-1,3-butadiene, are presentin a copolymer matrix, in particular of styrene and/or α-methylstyrene,and acrylonitrile.

In one preferred embodiment, in which the thermoplastic moldingcompositions comprise ABS polymers, the elastomeric graft copolymerA^(R)′, of component A is composed of

-   a1′ from 10 to 90% by weight of at least one elastomeric graft base    with a glass transition temperature below 0° C., obtainable by    polymerizing, based on A1′,-   a11′ from 60 to 100% by weight, preferably from 70 to 100% by    weight, of at least one conjugated diene and/or C₁-C₁₀-alkyl    acrylate, in particular butadiene, isoprene, n-butyl acrylate and/or    2-ethylhexyl acrylate,-   a12′ from 0 to 30% by weight, preferably from 0 to 25% by weight, of    at least one other monoethylenically unsaturated monomer, in    particular styrene, α-methyl-styrene, n-butyl acrylate, methyl    methacrylate, or a mixture of these, and among the last-named in    particular butadiene-styrene copolymers and n-butyl acrylate-styrene    copolymers, and-   a13′ from 0 to 10% by weight, preferably from 0 to 6% by weight, of    at least one crosslinking monomer, preferably divinylbenzene,    diallyl maleate, allyl (meth)acrylate, dihydrodicyclopentadienyl    acrylate, divinyl esters of dicarboxylic acids, such as succinic and    adipic acid, and diallyl and divinyl ethers of bifunctional    alcohols, such as ethylene glycol or butane-1,4-diol,-   a2′ from 10 to 60% by weight, preferably from 15 to 55% by weight,    of a graft A2′, composed of, based on A2′,-   a21′ from 50 to 100% by weight, preferably from 55 to 90% by weight,    of at least one vinylaromatic monomer, preferably styrene and/or    α-methylstyrene,-   a22′ from 5 to 35% by weight, preferably from 10 to 30% by weight,    of acrylonitrile and/or methacrylonitrile, preferably acrylonitrile,-   a23′ from 0 to 50% by weight, preferably from 0 to 30% by weight, of    at least one other monoethylenically unsaturated monomer, preferably    methyl methacrylate and n-butyl acrylate.

In another preferred embodiment in which the thermoplastic moldingcompositions comprise ABS, component A^(R)′ is a graft rubber withbimodal particle size distribution, composed of, based on A^(R)′,

-   a1″ from 40 to 90% by weight, preferably from 45 to 85% by weight,    of an elastomeric particulate graft base A1″, obtainable by    polymerizing, based on A1″,-   a11″ from 70 to 100% by weight, preferably from 75 to 100% by    weight, of at least one conjugated diene, in particular butadiene    and/or isoprene,-   a12″ from 0 to 30% by weight, preferably from 0 to 25% by weight, of    at least one other monoethylenically unsaturated monomer, in    particular styrene, α-methyl-styrene, n-butyl acrylate, or a mixture    of these,-   a2″ from 10 to 60% by weight, preferably from 15 to 55% by weight,    of a graft A2″ composed of, based on A2″,-   a21″ from 65 to 95% by weight, preferably from 70 to 90% by weight,    of at least one vinylaromatic monomer, preferably styrene,-   a22″ from 5 to 35% by weight, preferably from 10 to 30% by weight,    of acrylonitrile,-   a23″ from 0 to 30% by weight, preferably from 0 to 20% by weight, of    at least one other monoethylenically unsaturated monomer, preferably    methyl methacrylate and n-butyl acrylate.

In one preferred embodiment, in which the thermoplastic moldingcompositions comprise ASA polymers as component A, the hard matrix A^(M)of component A is at least one hard copolymer which comprises unitswhich derive from vinylaromatic monomers, and comprising, based on thetotal weight of units deriving from vinylaromatic monomers, from 0 to100% by weight, preferably from 40 to 100% by weight, particularlypreferably from 60 to 100% by weight, of units deriving fromα-methylstyrene, and comprising from 0 to 100% by weight, preferablyfrom 0 to 60% by weight, particularly preferably from 0 to 40% byweight, of units deriving from styrene, composed of, based on A^(M),

-   a^(M)1 from 40 to 100% by weight, preferably from 60 to 85% by    weight, of vinylaromatic units, as component A^(M) 1,-   a^(M)2 up to 60% by weight, preferably from 15 to 40% by weight, of    units of acrylonitrile or of methacrylonitrile, in particular of    acrylonitrile, as component A^(M)2.

In one preferred embodiment, in which the thermoplastic moldingcompositions comprise ABS polymers as component A, the hard matrixA^(M)′ of component A is at least one hard copolymer which comprisesunits which derive from vinylaromatic monomers, and comprising, based onthe total weight of units deriving from vinylaromatic monomers, from 0to 100% by weight, preferably from 40 to 100% by weight, particularlypreferably from 60 to 100% by weight, of units deriving fromα-methylstyrene, and from 0 to 100% by weight, preferably from 0 to 60%by weight, particularly preferably from 0 to 40% by weight, of unitsderiving from styrene, composed of, based on A^(M)′,

-   a^(M)1′ from 50 to 100% by weight, preferably from 55 to 90% by    weight, of vinylaromatic monomers,-   a^(M)2′ from 0 to 50% by weight of acrylonitrile or    methacrylonitrile or a mixture of these,-   a^(M)3′ from 0 to 50% by weight of at least one other    monoethylenically unsaturated monomer, such as methyl methacrylate    and N-alkyl- or N-arylmaleimides, e.g. N-phenylmaleimide.

In another preferred embodiment, in which the thermoplastic moldingcompositions comprise ABS as component A, component A^(M′) is at leastone hard copolymer with a viscosity number VN (determined to DIN 53726at 25° C. in 0.5% strength by weight solution in dimethylformamide) offrom 50 to 120 ml/g, comprising units which derive from vinylaromaticmonomers, and comprising, based on the total weight of units derivingfrom vinylaromatic monomers, from 0 to 100% by weight, preferably from40 to 100% by weight, particularly preferably from 60 to 100% by weight,of units deriving from α-methylstyrene, and from 0 to 100% by weight,preferably from 0 to 60% by weight, particularly preferably from 0 to40% by weight, of units deriving from styrene, composed of, based onA^(M)′,

-   a_(M)1″ from 69 to 81% by weight, preferably from 70 to 78% by    weight, of vinylaromatic monomers,-   a_(M)2″ from 19 to 31% by weight, preferably from 22 to 30% by    weight, of acrylonitrile,-   a_(M) ³″ from 0 to 30% by weight, preferably from 0 to 28% by    weight, of at least one other monoethylenically unsaturated monomer,    such as methyl methacrylate or N-alkyl- or N-arylmaleimides, e.g.    N-phenylmaleimide.

In one embodiment the ABS polymers comprise, alongside one another,components A^(M)′ whose viscosity numbers VN differ by at least fiveunits (ml/g) and/or whose acrylonitrile contents differ by five units (%by weight). Finally, alongside component A^(M)′ and the otherembodiments, there may also be copolymers present of α-methyl)-styrenewith maleic anhydride or maleimides, of α-methyl)styrene with maleimidesand methyl methacrylate or acrylonitrile, or of α-methyl)styrene withmaleimides, methyl methacrylate, and acrylonitrile.

In these ABS polymers, the graft polymers A^(R)′ are preferably obtainedby means of emulsion polymerization. The mixing of the graft polymersA^(R)′ with components A^(M)′, and, if appropriate, other additionsgenerally takes place in a mixing apparatus, producing a substantiallymolten polymer mixture. It is advantageous for the molten polymermixture to be cooled very rapidly.

In other respects, the preparation process and general embodiments, andparticular embodiments, of the abovementioned ABS polymers are describedin detail in the German patent application DE-A 19728629, expresslyincorporated herein by way of reference.

The ABS polymers mentioned may comprise other conventional auxiliariesand fillers. Examples of these substances are lubricants andmold-release agents, waxes, pigments, dyes, flame retardants,antioxidants, light stabilizers, and antistatic agents.

According to one preferred embodiment of the invention, the viscositynumber of the hard matrices A^(M) and, respectively, A^(M)′ of componentA is from 50 to 90, preferably from 60 to 80.

The hard matrices A^(M) and A^(M)′ of component A are preferablyamorphous polymers.

According to one embodiment of the invention, mixtures of a copolymer ofstyrene with acrylonitrile and of a copolymer composed ofα-methylstyrene with acrylonitrile are used as hard matrices A^(M) and,respectively, A^(M)′ of component A. The acrylonitrile content in thesecopolymers of the hard matrices is from 0 to 60% by weight, preferablyfrom 15 to 40% by weight, based on the total weight of the hard matrix.The hard matrices A^(M) and, respectively, A^(M)′ of component A alsoinclude the free, ungrafted (α-methyl)styrene-acrylonitrile copolymersproduced during the graft copolymerization reaction for preparingcomponent A^(R) and, respectively, A^(R)′. Depending on the conditionsselected during the graft copolymerization reaction for preparing thegraft copolymers A^(R) and, respectively, A^(R)′ it can be possible fora sufficient proportion of hard matrix to have been formed before thegraft copolymerization reaction has ended. However, it will generally benecessary for the products obtained during the graft copolymerizationreaction to be blended with additional, separately prepared hard matrix.

The additional, separately prepared hard matrices A^(M) and,respectively, A^(M)′ of component A may be obtained by the conventionalprocesses. For example, according to one embodiment of the invention thecopolymerization reaction of the styrene and/or α-methylstyrene with theacrylonitrile may be carried out in bulk, solution, suspension, oraqueous emulsion. The viscosity number of component A^(M) and,respectively, A^(M)′ is preferably from 40 to 100, with preference from50 to 90, in particular from 60 to 80. The viscosity number here isdetermined to DIN 53 726, dissolving 0.5 g of material in 100 ml ofdimethylformamide.

The mixing of components A^(R) (and, respectively, A^(R)′) andA^(M)(and, respectively, A^(M)′) may take place in any desired manner byany of the known methods. If, by way of example, these components havebeen prepared via emulsion polymerization, it is possible to mix theresultant polymer dispersions with one another, then to precipitate thepolymers together and work up the polymer mixture. However, thesecomponents are preferably blended via rolling or kneading or extrusionof the components together, the components having been isolated, ifnecessary, in advance from the aqueous dispersion or solution obtainedduring the polymerization reaction. The graft copolymerization productsobtained in aqueous dispersion may also be only partially dewatered andmixed in the form of moist crumb with the hard matrix, whereupon thenthe complete drying of the graft copolymers takes place during themixing process.

Styrene-Based Thermoplastic Elastomers:

Preferred styrene-based thermoplastic elastomers (S-TPE) are those whosetensile strain at break is more than 300%, particularly preferably morethan 500%, in particular more than 500% to 600%. The S-TPE admixedparticularly preferably comprises a linear or star-shapedstyrene-butadiene block copolymer having external polystyrene blocks Sand, situated between these, styrene-butadiene copolymer blocks havingrandom styrene/butadiene distribution (S/B)_(random) or having a styrenegradient (S/B)_(taper) (e.g. Styroflex® or Styrolux® from BASFAktiengesellschaft, K-Resin™ from CPC).

The total butadiene content is preferably in the range from 15 to 50% byweight, particularly preferably in the range from 25 to 40% by weight,and the total styrene content is correspondingly preferably in the rangefrom 50 to 85% by weight, particularly preferably in the range from 60to 75% by weight.

The styrene-butadiene block (S/B) is preferably composed of from 30 to75% by weight of styrene and from 25 to 70% by weight of butadiene. An(S/B) block particularly preferably has a butadiene content of from 35to 70% by weight and a styrene content of from 30 to 65% by weight.

The content of the polystyrene blocks S is preferably in the range from5 to 40% by weight, in particular in the range from 25 to 35% by weight,based on the entire block copolymer. The content of the S/B copolymerblocks is preferably in the range from 60 to 95% by weight, inparticular in the range from 65 to 75% by weight.

Particular preference is given to linear styrene-butadiene blockcopolymers of the general structure S-(S/B)-S having, situated betweenthe two S blocks, one or more (S/B)_(random) blocks having randomstyrene/butadiene distribution. Block copolymers of this type areobtainable via anionic polymerization in a non-polar solvent withaddition of a polar cosolvent or of a potassium salt, as described byway of example in WO 95/35335 or WO 97/40079.

The vinyl content is the relative content of 1,2-linkages of the dieneunits, based on the entirety of 1,2-, and 1,4-cis and 1,4-translinkages. The 1,2-vinyl content in the styrene/butadiene copolymer block(S/B) is preferably below 20%, in particular in the range from 10 to18%, particularly preferably in the range from 12 to 16%.

Polyolefins:

The polyolefins that can be used as components A generally have tensilestrain at break values of from 10% to 600%, preferably from 15% to 500%,particularly preferably from 20% to 400%.

Examples of suitable components A are semicrystalline polyolefins, suchas homo- or copolymers of ethylene, propylene, 1-butene, 1-pentene,1-hexene, or 4-methyl-1-pentene, and ethylene copolymers with vinylacetate, vinyl alcohol, ethyl acrylate, butyl acrylate, or methacrylate.The component A used preferably comprises a high-density polyethylene(HDPE), low-density polyethylene (LDPE), linear low-density polyethylene(LLDPE), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), orethylene-acrylic copolymer. A particularly preferred component A ispolypropylene.

Polycarbonates:

The polycarbonates that can be used as components A generally havetensile strain at break values of from 20% to 300%, preferably from 30%to 250%, particularly preferably from 40% to 200%.

The molar mass of polycarbonates suitable as component A (weight averageM_(w), determined by means of gel permeation chromatography intetrahydrofuran against polystyrene standards) is preferably in therange from 10 000 to 60 000 g/mol. By way of example, they areobtainable by the processes of DE-B-1 300 266 via interfacialpolycondensation or according to the process of DE-A-1 495 730 viareaction of diphenyl carbonate with bisphenols. Preferred bisphenol is2,2-di(4-hydroxy-phenyl)propane, generally—and also hereinafter—termedbisphenol A.

Instead of bisphenol A, it is also possible to use other aromaticdihydroxy compounds, in particular 2,2-di(4-hydroxyphenyl)pentane,2,6-dihydroxynaphthalene, 4,4′-di-hydroxydiphenyl sulfone,4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenyl sulfite,4,4′-dihydroxydiphenylmethane, 1,1-di(4-hydroxyphenyl)ethane,4,4-dihydroxydiphenyl, or dihydroxydiphenylcycloalkanes, preferablydihydroxydiphenylcyclohexanes, or dihydroxycyclopentanes, in particular1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, or else a mixtureof the abovementioned dihydroxy compounds.

Particularly preferred polycarbonates are those based on bisphenol A orbisphenol A together with up to 80 mol % of the abovementioned aromaticdihydroxy compounds.

Polycarbonates with particularly good suitability as component A arethose which comprise units that derive from resorcinol esters or fromalkylresorcinol esters, for example those described in WO 00/61664, WO00/15718, or WO 00/26274. These polycarbonates are marketed by way ofexample by General Electric Company, the trademark being SollX®.

It is also possible to use copolycarbonates according to U.S. Pat. No.3,737,409, and copolycarbonates based on bisphenol A anddi(3,5-dimethyldihydroxyphenyl) sulfone are of particular interest here,and feature high heat resistance. It is also possible to use mixtures ofdifferent polycarbonates.

The average molar masses (weight average M_(w), determined by means ofgel permeation chromatography in tetrahydrofuran against polystyrenestandards) of the polycarbonates are in the range from 10 000 to 64 000g/mol. They are preferably in the range from 15 000 to 63 000 g/mol, inparticular in the range from 15 000 to 60 000 g/mol. This means that therelative solution viscosities of the polycarbonates are in the rangefrom 1.1 to 1.3, measured in 0.5% strength by weight solution indichloromethane at 25° C., preferably from 1.15 to 1.33. The differencebetween the relative solution viscosities of the polycarbonates used ispreferably not more than 0.05, in particular not more than 0.04.

The form in which the polycarbonates are used may either be that ofregrind or else that of pellets.

Thermoplastic Polyurethane:

Any aromatic or aliphatic thermoplastic polyurethane is generallysuitable as component A, and amorphous aliphatic thermoplasticpolyurethanes which are transparent have preferred suitability.Aliphatic thermoplastic polyurethanes and their preparation are known tothe person skilled in the art, for example from EP-B1 567 883 or DE-A10321081, and are commercially available, for example with trademarksTexin® and Desmopan® from Bayer Aktiengesellschaft.

The Shore hardness D of preferred aliphatic thermoplastic polyurethanesis from 45 to 70, and their tensile strain at break values are from 30%to 800%, preferably from 50% to 600%, particularly preferably from 80%to 500%.

Particularly preferred components A are the styrene-based thermoplasticelastomers.

Component B

The thermoplastic molding compositions comprise carbon nanotubes ascomponent B. Carbon nanotubes and their preparation are known to theperson skilled in the art and are described in the literature, forexample in US 2005/0186378 A1. Carbon nanotubes can by way of example besynthesized in a reactor which comprises a metal catalyst and a gascomprising carbon (see, for example, U.S. Pat. No. 5,643,502). Carbonnanotubes are marketed, for example by Hyperion Catalysis, or AppliedSciences Inc.

Preferred carbon nanotubes typically have a single- or multiwall tubularstructure. Single-wall carbon nanotubes (SWCN) are formed from a singlegraphitic carbon layer, and multiwall carbon nanotubes (MWCN) are formedfrom a plurality of such graphitic carbon layers. The graphite layershave a concentric arrangement around the axis of the cylinder. Thelength-to-diameter ratio of carbon nanotubes is generally at least 5,preferably at least 100, particularly preferably at least 1000. Thediameter of the nanotubes is typically in the range from 0.002 to 0.5μm, preferably in the range from 0.005 to 0.08 μm, particularlypreferably in the range from 0.006 to 0.05 μm. The length of the carbonnanotubes is typically from 0.5 to 1000 μm, preferably from 0.8 to 100μm, particularly preferably from 1 to 10 μm. The carbon nanotubes have ahollow cylindrical core around which the graphite layers have formallybeen wound. The diameter of this cavity is typically from 0.001 to 0.1μm, preferably from 0.008 to 0.015 μm. In a typical embodiment of thecarbon nanotubes, the wall of the tubes around the cavity is composed byway of example of 8 graphite sublayers. The carbon nanotubes here cantake the form of aggregates of up to 1000 μm in diameter, preferably upto 500 μm in diameter, composed of a plurality of nanotubes. Theaggregates can take the form of nests, of combed yarn, or of opennetwork structures.

The carbon nanotubes can be added prior to, during, or after thepolymerization of the monomers to give the thermoplastic polymer ofcomponent A. If the nanotubes are added after the polymerization, theyare preferably added via addition to the thermoplastic melt in anextruder or preferably in a kneader. The compounding procedure in thekneader or extruder can in particular comminute the aggregates describedabove substantially or even entirely and disperse the carbon nanotubesin the thermoplastic matrix.

In one preferred embodiment, the form in which the carbon nanotubes arefed can be that of highly concentrated masterbatches in thermoplastics,which are preferably selected from the group of the thermoplastics usedas component A. The concentration of the carbon nanotubes in themasterbatches is usually in the range from 5 to 50% by weight,preferably from 8 to 30% by weight, particularly preferably in the rangefrom 12 to 22% by weight. The preparation of masterbatches is describedby way of example in U.S. Pat. No. 5,643,502. Use of masterbatches canin particular improve the commination of the aggregates. The lengthdistributions of the carbon nanotubes in the molding composition or inthe molding can be shorter than that of those originally used, by virtueof processing to give the molding composition or to give the molding.

Component C

In principle, any of the dispersing agents described in the prior artand known to the person skilled in the art for use in plastics mixturesis suitable as component C. Preferred dispersing agents are surfactantsor surfactant mixtures, such as anionic, cationic, amphoteric ornonionic surfactants. Further preference is given to the oligomeric andpolymeric dispersing agents commercially available and known to theperson skilled in the art as described in CD Römpp Chemie Lexikon [CDRömpp chemical encyclopedia]—Version 3.0, Stuttgart/N.Y.: Georg ThiemeVerlag 2006, keyword “Dispergierhilfsmittel” [dispersing agents].

Examples are polycarboxylic acids, polyamines, salts composed oflong-chain polyamines and polycarboxylic acids, amine/amide-functionalpolyesters and polyacrylates, soy lecithins, polyphosphates, modifiedcaseins. These polymeric dispersing agents can be present in the form ofblock copolymers, comb polymers, or random copolymers.

Cationic and anionic surfactants are described by way of example in“Encyclopedia of Polymer Science and Technology”, J. Wiley & Sons(1966), Volume 5, pp. 816 to 818, and in “Emulsion Polymerisation andEmulsion Polymers”, editors P. Lovell and M. El-Asser, published byWiley & Sons (1997), pp. 224-226.

Examples of anionic surfactants are alkali metal salts of organiccarboxylic acids having chain lengths of from 8 to 30 carbon atoms,preferably from 12 to 18 carbon atoms. These are generally termed soaps.The salts usually used are the sodium, potassium, or ammonium salts.Other anionic surfactants which may be used are alkyl sulfates andalkyl- or alkylarylsulfonates having from 8 to 30 carbon atoms,preferably from 12 to 18 carbon atoms. Particularly suitable compoundsare alkali metal dodecyl sulfates, e.g. sodium dodecyl sulfate orpotassium dodecyl sulfate, and alkali metal salts of C₁₂-C₁₆paraffinsulfonic acids. Other suitable compounds are sodiumdodecylbenzenesulfonate and sodium dioctyl sulfosuccinate.

Examples of suitable cationic surfactants are salts of amines or ofdiamines, quaternary ammonium salts, e.g. hexadecyltrimethylammoniumbromide, and also salts of long-chain substituted cyclic amines, such aspyridine, morpholine, piperidine. Use is particularly made of quaternaryammonium salts of trialkylamines, e.g. hexadecyltri-methylammoniumbromide. The alkyl radicals here preferably have from 1 to 20 carbonatoms.

Nonionic surfactants may in particular be used as component C. Nonionicsurfactants are described by way of example in CD Römpp ChemieLexikon—Version 1.0, Stuttgart/N.Y.: Georg Thieme Verlag 1995, keyword“Nichtionische Tenside” [Nonionic surfactants].

Examples of suitable nonionic surfactants are polyethylene-oxide- orpolypropylene-oxide-based substances, such as Pluronic® or Tetronic®from BASF Aktiengesellschaft. Polyalkylene glycols suitable as nonionicsurfactants generally have a molar mass M_(n) in the range from 1 000 to15 000 g/mol, preferably from 2 000 to 13 000 g/mol, particularlypreferably from 4 000 to 11 000 g/mol. Preferred nonionic surfactantsare polyethylene glycols.

The polyalkylene glycols are known per se or may be prepared byprocesses known per se, for example by anionic polymerization usingalkali metal hydroxide catalysts, such as sodium hydroxide or potassiumhydroxide, or using alkali metal alkoxide catalysts, such as sodiummethoxide, sodium ethoxide, potassium ethoxide or potassiumisopropoxide, and with addition of at least one starter molecule whichcomprises from 2 to 8 reactive hydrogen atoms, preferably from 2 to 6reactive hydrogen atoms, or by cationic polymerization using Lewis acidcatalysts, such as antimony pentachloride, boron fluoride etherate, orbleaching earth, the starting materials being one or more alkyleneoxides having from 2 to 4 carbon atoms in the alkylene radical.

Examples of suitable alkylene oxides are tetrahydrofuran, butylene 1,2-or 2,3-oxide, styrene oxide, and preferably ethylene oxide and/orpropylene 1,2-oxide. The alkylene oxides may be used individually,alternating one after the other, or as a mixture. Examples of startermolecules which may be used are: water, organic dicarboxylic acids, suchas succinic acid, adipic acid, phthalic acid, or terephthalic acid,aliphatic or aromatic, unsubstituted or N-mono-, or N,N- orN,N′-dialkyl-substituted diamines having from 1 to 4 carbon atoms in thealkyl radical, such as unsubstituted or mono- or dialkyl-substitutedethylenediamine, diethylenetriamine, triethylenetetramine,1,3-propylene-diamine, 1,3- or 1,4-butylenediamine, or 1,2-, 1,3-, 1,4-,1,5- or 1,6-hexamethylene-diamine.

Other starter molecules which may be used are: alkanolamines, e.g.ethanolamine, N-methyl- and N-ethylethanolamine, dialkanolamines, e.g.diethanolamine, and N-methyl- and N-ethyldiethanolamine, andtrialkanolamines, e.g. triethanolamine, and ammonia. It is preferable touse polyhydric alcohols, in particular di- or trihydric alcohols oralcohols with functionality higher than three, for example ethanediol,1,2-propanediol, 1,3-propanediol, diethylene glycol, dipropylene glycol,1,4-butanediol, 1,6-hexanediol, glycerol, trimethylolpropane,pentaerythritol, sucrose, and sorbitol.

Other suitable components C are esterified polyalkylene glycols, such asthe mono-, di-, tri- or polyesters of the polyalkylene glycols mentionedwhich can be prepared by reacting the terminal OH groups of thepolyalkylene glycols mentioned with organic acids, preferably adipicacid or terephthalic acid, in a manner known per se. Polyethylene glycoladipate or polyethylene glycol terephthalate is preferred as componentC.

Particularly suitable nonionic surfactants are substances prepared byalkoxylating compounds having active hydrogen atoms, for example adductsof ethylene oxide onto fatty alcohols, oxo alcohols, or alkylphenols. Itis preferable to use ethylene oxide or 1,2-propylene oxide for thealkoxylation reaction.

Other preferred nonionic surfactants are alkoxylated or nonalkoxylatedsugar esters or sugar ethers.

Sugar ethers are alkyl glycosides obtained by reacting fatty alcoholswith sugars, and sugar esters are obtained by reacting sugars with fattyacids. The sugars, fatty alcohols, and fatty acids needed to prepare thesubstances mentioned are known to the person skilled in the art.

Suitable sugars are described by way of example in Beyer/Walter,Lehrbuch der organischen Chemie [Textbook of organic chemistry], S.Hirzel Verlag Stuttgart, 19th edition, 1981, pp. 392 to 425.Particularly suitable sugars are D-sorbitol and the sorbitans obtainedby dehydrating D-sorbitol.

Suitable fatty acids are saturated or singly or multiply unsaturatedunbranched or branched carboxylic acids having from 6 to 26 carbonatoms, preferably from 8 to 22 carbon atoms, particularly preferablyfrom 10 to 20 carbon atoms, for example as mentioned in CD Römpp ChemieLexikon—Version 1.0, Stuttgart/N.Y.: Georg Thieme Verlag 1995, keyword“Fettsäuren” [Fatty acids]. Preferred fatty acids are lauric acid,palmitic acid, stearic acid, and oleic acid.

The carbon skeleton of suitable fatty alcohols is identical with that ofthe compounds described as suitable fatty acids.

Sugar ethers, sugar esters, and the processes for their preparation areknown to the person skilled in the art. Preferred sugar ethers areprepared by known processes, by reacting the sugars mentioned with thefatty alcohols mentioned. Preferred sugar esters are prepared by knownprocesses, by reacting the sugars mentioned with the fatty acidsmentioned. Preferred sugar esters are the mono-, di-, and triesters ofthe sorbitans with fatty acids, in particular sorbitan monolaurate,sorbitan dilaurate, sorbitan trilaurate, sorbitan monooleate, sorbitandioleate, sorbitan trioleate, sorbitan monopalmitate, sorbitandipalmitate, sorbitan tripalmitate, sorbitan monostearate, sorbitandistearate, sorbitan tristearate, and sorbitan sesquioleate, a mixtureof sorbitan mono- and dioleates.

Component D

The thermoplastic molding compositions comprise, as component D, fibrousor particulate fillers other than component B, or a mixture of these.These are preferably commercially available products, such as carbonfibers and glass fibers.

Glass fibers that may be used may be composed of E, A, or C glass, andhave preferably been treated with a size and with a coupling agent.Their diameter is generally from 6 to 20 μm. It is possible to useeither continuous-filament fibers (rovings) or else chopped glass fibers(staple) whose length is from 1 to 10 mm, preferably from 3 to 6 mm.

It is also possible to add fillers or reinforcing materials, such asglass beads, mineral fibers, whiskers, aluminum oxide fibers, mica,powdered quartz, and wollastonite.

The thermoplastic molding compositions may moreover comprise otheradditions which are typical of, and customary in, plastics mixtures.

By way of example of these additions, mention may be made of: dyes,pigments, colorants, antistatic agents, antioxidants, stabilizers forimproving heat resistance, for increasing resistance to light, forraising resistance to hydrolysis and to chemicals, agents to counterdecomposition by heat, and in particular the lubricants that areadvantageous for production of moldings. These other additions may bemetered in at any stage of the production process, but preferably at anearly juncture, in order that the stabilizing effects (or other specificeffects) of the addition may be utilized at an early stage. Heatstabilizers or oxidation retarders are usually metal halides (chlorides,bromides, iodides) derived from metals of group I of the Periodic Tableof the Elements (e.g. Li, Na, K, Cu).

Suitable stabilizers are the conventional hindered phenols, but alsovitamin E or analogous-structure compounds. HALS stabilizers (HinderedAmine Light Stabilizers), benzophenones, resorcinols, salicylates,benzotriazoles, such as Tinuvin® RP (the UV absorber2-(2H-benzotriazol-2-yl)-4-methylphenol from CIBA), and other compoundsare also suitable. The amounts of these usually used are up to 2% byweight (based on the entire thermoplastic molding composition mixture).

Suitable lubricants and mold-release agents are stearic acids, stearylalcohol, stearic esters, and generally higher fatty acids, theirderivatives, and corresponding fatty acid mixtures having from 12 to 30carbon atoms. The amounts of these additions are in the range from 0.05to 1% by weight.

Silicone oils, oligomeric isobutylene, or similar substances may also beused as additives, and the usual amounts are from 0.05 to 5% by weight.It is also possible to use pigments, dyes, color brighteners, such asultramarine blue, phthalocyanines, titanium dioxide, cadmium sulfides,derivatives of perylenetetracarboxylic acid.

The amounts usually used of processing aids and stabilizers, such as UVstabilizers, lubricants, and antistatic agents, are from 0.01 to 5% byweight.

Process for Production of Metallizable Substrates

The thermoplastic molding compositions are prepared from components A,B, and, if present, C and D by processes known to the person skilled inthe art, for example via mixing of the components in the melt, usingapparatuses known to the person skilled in the art at temperatures whichas a function of the nature of the polymer A used are usually in therange from 150° C. to 300° C., in particular from 200° C. to 280° C.Each of the components here can be introduced in pure form into themixing apparatuses. However, it is also possible to begin by premixingindividual components, such as A and B or A and C, and then to mix thesewith further components A, B, and/or C, or with other components, suchas D. In one embodiment, a concentrate is first prepared, these beingknown as additive masterbatches, for example from components B, C, or Din component A, and this is then mixed with the desired amounts of theremaining components. The thermoplastic molding compositions can bepelletized by processes known to the person skilled in the art, for, byway of example, subsequent processing via extrusion, injection molding,calendering, or compression molding to give metallizable moldings (i.e.substrates), such as foils or sheets or composite layered foils orcomposite layered sheets. However, they can also be processed, inparticular extruded or injection molded, directly after the mixingprocedure or in a single operation with the mixing procedure (i.e.simultaneous mixing in the melt and preferably extrusion, preferably bymeans of a screw extruder, or injection molding) to give metallizablemoldings, such as foils or sheets.

In one preferred embodiment of the processes by means of extrusion, thescrew extruder has been designed as a single-screw extruder with atleast one distributively mixing screw element.

In a further preferred embodiment of the processes, the screw extruderhas been designed as a twin-screw extruder with at least onedistributively mixing screw element.

The processes for extrusion of the metallizable moldings can be carriedout by methods described in the prior art and known to the personskilled in the art, e.g. slot extrusion in the form of adaptorcoextrusion or die coextrusion, and the use of the apparatuses describedin the prior art and known to the person skilled in the art. Theprocesses for injection molding, calendering, or compression molding ofthe metallizable moldings are likewise known to the person skilled inthe art and described in the prior art.

The total thickness of metallizable moldings in the form of foils orsheets is generally from 10 μm to 5 mm, preferably from 10 μm to 3 mm,particularly preferably from 20 μm to 1.5 mm, in particular from 100 μmto 400 μm.

The metallizable moldings can be subjected to further shaping processesconventional in plastics processing technology.

Moldings Obtainable Via Further Shaping Processes:

The metallizable foils or sheets or composite layered sheets orcomposite layered foils can be used for production of further moldings.Any desired moldings are accessible here, preference being given tosheet-like moldings, in particular large-surface-area moldings. Thesefoils or sheets and composite layered sheets or composite layered foilsare particularly preferably used for production of further moldings inwhich very good toughness values, good adhesion of the individual layersto one another, and good dimensional stability are important, thus byway of example minimizing breakdown via peel of the surfaces.Particularly preferred moldings which are obtainable by further shapingprocesses have monofoils or composite layered sheets or compositelayered foils and a backing layer composed of plastic applied to theback of the material by an injection-molding, foaming, casting, orcompression-molding process.

Processes that are known and described by way of example in WO 04/00935can be used for production of these moldings from the metallizable foilsor sheets or from the metallizable composite layered sheets ormetallizable composite layered foils (the processes for furtherprocessing of composite layered sheets or composite layered foils beingdescribed below, but these processes also being capable of use forfurther processing the foils or sheets). The material can be applied tothe back of the composite layered sheets or composite layered foils byan injection-molding, foaming, casting, or compression-molding process,without any further stage of processing. In particular, the use of thecomposite layered sheets or composite layered foils described permitsproduction even of slightly three-dimensional components without priorthermoforming. The composite layered sheets or composite layered foilsmay, however, also be subjected to a prior thermoforming process.

By way of example, it is possible to thermoform composite layered sheetsor composite layered foils with the three-layered structure composed ofbacking layer, intermediate layer, and outer layer, or the two-layerstructure composed of backing layer and outer layer, to producerelatively complex components. Either positive or negative thermoformingprocesses can be used here. Appropriate processes are known to theperson skilled in the art. The composite layered sheets or compositelayered foils here are oriented in the thermoforming process. Since thesurface quality and metallizability of the composite layered sheets orcomposite layered foils does not decrease with orientation at highorientation ratios, for example up to 1:5, there are almost norestrictions relating to the possible orientation in the thermoformingprocesses. After the thermoforming process, the composite layered sheetsor foils can be subjected to still further shaping steps, for exampleprofile cuts.

The further metallizable moldings can be produced, if appropriate afterthe thermoforming processes described, by applying material to the backof the composite layered sheets or composite layered foils viainjection-molding, foaming, casting, or compression-molding processes.These methods are known to the person skilled in the art and aredescribed by way of example in DE-A1 100 55 190 or DE-A1 199 39 111.

The plastics materials applied in these injection-molding,compression-molding, or casting processes preferably comprisethermoplastic molding compositions based on ASA polymers, on ABSpolymers, on SAN polymers, on poly(meth)acrylates, on polyethersulfones, on polybutylene terephthalate, on polycarbonates, onpolypropylene (PP), or on polyethylene (PE), or else blends composed ofASA polymers or of ABS polymers and of polycarbonates or polybutyleneterephthalate, and blends composed of polycarbonates and polybutyleneterephthalate, and if PP and/or PE is used here it is clearly possibleto provide the substrate layer in advance with an adhesion-promoterlayer. Particularly suitable materials are amorphous thermoplastics andtheir blends. The plastics material preferably used for application tothe back of the material by an injection-molding process is ABS polymersor SAN polymers. In another preferred embodiment, thermoset moldingcompositions known to the person skilled in the art are used forapplication to the back of the material by a foaming orcompression-molding process. In one preferred embodiment, these areglass-fiber-reinforced plastics materials, and suitable variants are inparticular described in DE-A1 100 55 190. For application to the back ofthe material by a foaming process it is preferable to use polyurethanefoams, for example those described in DE-A1 199 39 111.

In one preferred production process the metallizable composite layeredsheet or composite layered foil is thermoformed and then placed in aback-molding mold, and thermoplastics are applied to the back of thematerial by an injection-molding, casting, or compression-moldingprocess, or thermoset plastics are applied to the back of the materialby a foaming or compression-molding process.

After thermoforming and prior to placement in the back-molding mold, thecomposite layered sheet or composite layered foil may undergo a profilecut. The profile cut can also be delayed until after removal from theback-molding mold.

Dispersions Comprising Carbon Nanotubes

In another preferred embodiment, the substrates that can be used in theinventive processes for deposition of a metal by a chemical and/orelectroplating method are those in which, prior to the step ofmetallizing by a chemical and/or electroplating method, the substrate isprovided with a dispersion comprising carbon nanotubes and thedispersion is at least partially dried and/or at least partiallyhardened.

Preferred dispersions comprising carbon nanotubes comprise, based on thetotal weight of components A′, B′, and C′, which is 100% by weight,

-   a′ from 0.1 to 99.9% by weight, preferably from 2 to 89.5% by    weight, particularly preferably from 4 to 84% by weight, of    component A′,-   b′ from 0.1 to 30% by weight, preferably from 0.5 to 20% by weight,    particularly preferably from 1 to 10% by weight, of component B′,    and-   c′ from 0 to 99.8% by weight, preferably from 10 to 97.5% by weight,    particularly preferably from 15 to 95% by weight, of component C′.

The dispersion can comprise, other than components A′ to C′ mentioned,at least one of the following components:

-   d′ from 0.1 to 50% by weight, preferably from 0.5 to 40% by weight,    particularly preferably from 1 to 20% by weight, based on the total    weight of components A′-C′, of a dispersing agent component D′; and    also-   e′ from 0 to 50% by weight, preferably from 0.1 to 40% by weight,    particularly preferably from 0.5 to 30% by weight, based on the    total weight of components A′-C′, of a filler component E different    from component B′.

The individual components of the dispersion are described below:

Component A′

The organic binder component A′ is a binder or binder mixture. Possiblebinders are binders having an anchor group that has pigment affinity,naturally occurring and synthetic polymers and their derivatives,naturally occurring resins and synthetic resins and their derivatives,natural rubber, synthetic rubber, proteins, cellulose derivatives,drying and non-drying oils, and the like. These can—but do not have tobe—substances that cure chemically or physically, for exampleair-curing, radiation-curing, or heat-curing substances.

The binder component A′ is preferably a polymer or polymer mixture.

Polymers preferred as binder are ABS (acrylonitrile-butadiene-styrene);ASA (acrylonitrile-styrene-acrylate); acrylated acrylates; alkyd resins;alkylvinyl acetates; alkylene-vinyl acetate copolymers, in particularmethylene-vinyl acetate, ethylene-vinyl acetate, butylene-vinyl acetate;alkylene-vinyl chloride copolymers; amino resins; aldehyde resins andketone resins; cellulose and cellulose derivatives, in particularhydroxyalkylcellulose, cellulose esters, such as cellulose acetates,cellulose propionates, cellulose butyrates, carboxyalkylcelluloses,cellulose nitrate; epoxy acrylates; epoxy resins; modified epoxy resins,e.g. bifunctional or polyfunctional bisphenol A or bisphenol F resins,epoxy-novolak resins, brominated epoxy resins, cycloaliphatic epoxyresins; aliphatic epoxy resins, glycidic ethers, vinyl ethers,ethylene-acrylic acid copolymers; hydrocarbon resins; MABS (transparentABS comprising acrylate units present); melamine resins, maleicanhydride copolymers; methacrylates; natural rubber; synthetic rubber;chlorinated rubber; naturally occurring resins; rosins; shellac;phenolic resins; polyesters; polyester resins, such as phenyl esterresins; polysulfones; polyether sulfones; polyamides; polyimides;polyanilines; polypyrroles; polybutylene terephthalate (PBT);polycarbonate (e.g. Makrolon® from Bayer AG); polyester acrylates;polyether acrylates; polyethylene; polyethylene-thiophenes; polyethylenenaphthalates; polyethylene terephthalate (PET); polyethyleneterephthalate glycol (PETG); polypropylene; polymethyl methacrylate(PMMA); polyphenylene oxide (PPO); polystyrenes (PS),polytetrafluoroethylene (PTFE); polytetrahydrofuran; polyethers (e.g.polyethylene glycol, polypropylene glycol), polyvinyl compounds, inparticular polyvinyl chloride (PVC), PVC copolymers, PVdC, polyvinylacetate, and also copolymers of these, polyvinyl alcohol, if appropriatein partially hydrolyzed form, polyvinyl acetals, polyvinyl acetates,polyvinylpyrrolidone, polyvinyl ethers, polyvinyl acrylates andpolyvinyl methacrylates in solution and in the form of a dispersion, andalso copolymers of these, polyacrylates and polystyrene copolymers;polystyrene (impact-modified or non-impact-modified); polyurethanes,non-crosslinked or crosslinked with isocyanates; polyurethane acrylates,styrenic-acrylic copolymers; styrene-butadiene block copolymers (e.g.Styroflex® or Styrolux® from BASF AG, K-Resin™ from CPC, Kraton D orKraton G from Kraton Polymers); proteins, e.g. casein; SIS; triazineresin, bismaleimide-triazine resin (BT), cyanate ester resin (CE),allylated polyphenylene ethers (APPE).

Mixtures of two or more polymers may also form the organic bindercomponent A′.

Polymers preferred as component A′ are acrylates, acrylate resins,cellulose derivatives, methacrylates, methacrylate resins, melamine, andamino resins, polyalkylenes, polyimides, epoxy resins, modified epoxyresins, e.g. bifunctional or polyfunctional bisphenol A or bisphenol Fresins, epoxy-novolak resins, brominated epoxy resins, cycloaliphaticepoxy resins; aliphatic epoxy resins, glycidic ethers, vinyl ethers, andphenolic resins, polyurethanes, polyesters, polyvinyl acetals, polyvinylacetates, polystyrenes, polystyrene copolymers, polystyrene-acrylates,styrene-butadiene block copolymers, alkylene-vinyl acetates, and vinylchloride copolymers, polyamides, and also copolymers of these.

Component B′

The carbon nanotubes described above as component B can be used ascomponent B′.

In one embodiment of the invention, the carbon nanotubes can be added tothe dispersion by first incorporating the carbon nanotubes into thebinder component A′; if component A′ is a polymer or a polymer mixture,this incorporation can take place during or after the polymerization ofthe monomers to give the binder component A′. If the nanotubes are addedafter polymerization, they are preferably added via addition to thepolymer melt in an extruder or preferably in a kneader. The compoundingprocedure in the kneader or extruder can comminute aggregates or carbonnanotubes substantially or even entirely and disperse the carbonnanotubes in the polymer matrix.

In one preferred embodiment of the pre-incorporation of the carbonnanotubes into the binder component A′, the form in which the carbonnanotubes are metered into the binder component A′ can be that ofhigh-concentration masterbatches in polymers preferably selected fromthe group of the polymers used as component A′. The concentration of thecarbon nanotubes in the masterbatches is usually in the range from 5 to50% by weight, preferably from 8 to 30% by weight, particularlypreferably in the range from 12 to 22% by weight. The preparation ofmasterbatches is described by way of example in U.S. Pat. No. 5,643,502.Use of masterbatches can in particular improve the commination of theaggregates.

The length distributions of the carbon nanotubes can be shorter thanthat originally used, as a result of the incorporation into thedispersion or of the pre-incorporation into component A′.

Component C′

The dispersion moreover comprises a solvent component C′. This iscomposed of a solvent or of a solvent mixture.

Examples of suitable solvents are aliphatic and aromatic hydrocarbons(e.g. n-octane, cyclohexane, toluene, xylene), alcohols (e.g. methanol,ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, amyl alcohol),polyhydric alcohols, such as glycerol, ethylene glycol, propyleneglycol, neopentyl glycol, alkyl esters (e.g. methyl acetate, ethylacetate, propyl acetate, butyl acetate, isobutyl acetate, isopropylacetate, 3-methylbutanol), alkoxyalcohols (e.g. methoxypropanol,methoxybutanol, ethoxypropanol), alkylbenzenes (e.g. ethylbenzene,isopropylbenzene), butyl glycol, butyl diglycol, alkyl glycol acetates(e.g. butyl glycol acetate, butyl diglycol acetate), diacetone alcohol,diglycol dialkyl ethers, diglycol monoalkyl ethers, dipropylene diglycoldialkyl ethers, dipropylene glycol monoalkyl ethers, diglycol alkylether acetates, dipropylene glycol alkyl ether acetates, dioxane,dipropylene glycol and dipropylene glycol ethers, diethylene glycol anddiethylene glycol ethers, DBE (dibasic esters), ethers (e.g. diethylether, tetrahydrofuran), ethylene chloride, ethylene glycol, ethyleneglycol acetate, ethylene glycol dimethyl ether, cresol, lactones (e.g.butyrolactone), ketones (e.g. acetone, 2-butanone, cyclohexanone, methylethyl ketone (MEK), methyl isobutyl ketone (MIBK), methyl diglycol,methylene chloride, methylene glycol, methylglycol acetate, methylphenol(ortho-, meta-, para-cresol), pyrrolidones (e.g.N-methyl-2-pyrrolidone), propylene glycol, propylene carbonate, carbontetrachloride, toluene, trimethylolpropane (TMP), aromatic hydrocarbonsand mixtures, aliphatic hydrocarbons and mixtures, alcoholicmonoterpenes (e.g. terpineol), water, and also mixtures composed of twoor more of these solvents.

Preferred solvents are alcohols (e.g. ethanol, 1-propanol, 2-propanol,butanol), alkoxy alcohols (e.g. methoxypropanol, ethoxypropanol,butylglycol, butyldiglycol), butyrolactone, diglycol dialkyl ethers,diglycol monoalkyl ethers, dipropylene glycol dialkyl ethers,dipropylene glycol monoalkyl ethers, esters (e.g. ethyl acetate, butylacetate, butylglycol acetate, butyldiglycol acetate, diglycol alkylether acetates, dipropylene glycol ether acetates, DBE), ethers (e.g.tetrahydrofuran), polyhydric alcohols, such as glycerol, ethyleneglycol, propylene glycol, neopentyl glycol, ketones (e.g. acetone,methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone),hydrocarbons (e.g. cyclohexane, ethylbenzene, toluene, xylene),N-methyl-2-pyrrolidone, water, and also mixtures of these.

Component D′

The dispersion can moreover comprise, as dispersing agent component D′,the dispersing agent described above as component C.

Component E′

The dispersion can moreover comprise, as filler component E′, thefillers described above as component D.

The dispersions can moreover comprise, alongside the componentsmentioned A′, B′, C′, and, if appropriate, D′ and/or E′, furtheradditions, such as processing aids and stabilizers, e.g. UV stabilizers,lubricants, corrosion inhibitors, and flame retardants.

It is also possible to use further additives, such as agents withthixotropic effect, e.g. silica, silicates, e.g. Aerosils or bentonites,or organic agents with thixotropic effect and thickeners, e.g.polyacrylic acid, polyurethanes, hydrogenated castor oil, dyes, fattyacids, fatty acid amides, plasticizers, wetting agents, antifoams,lubricants, desiccants, crosslinking agents, photoinitiators, complexingagents, waxes, pigments, and conductive polymer particles.

The content of further additions, based on the total weight of thedispersion, is usually from 0.01 to 30% by weight. The content ispreferably from 0.1 to 10% by weight.

Preferred processes for preparation of the dispersion comprise thefollowing steps:

-   a′) mixing of components A′ to B′ and of at least one portion of    component C′, and also, if appropriate, D′, E′, and further    components,-   b′) dispersion of the mixture,-   c′) if appropriate, addition of the proportion not used in step a′)    of component C′ for adjustment of viscosity for the respective    application method.

The dispersion can be prepared via intensive mixing and dispersion usingassemblies known to persons skilled in the art. This includes mixing thecomponents in an intensive-dispersion assembly, e.g. kneaders, ballmills, bead mills, dissolvers, three-roll mills, or rotor-stator mixers.

It is possible to mix all of the desired components of the dispersion ina single step of the process. However, it is also possible to premix twoor more components, for example components A′ and B′, as describedabove, and to delay admixture of the remaining components to asubsequent separate step of the process.

One embodiment of the inventive processes for production of a metallayer on at least one portion of the surface of a substrate comprisesthe following steps:

-   a) application of a dispersion comprising carbon nanotubes to the    substrate;-   b) at least partial drying and/or at least partial hardening of the    layer applied on the substrate; and-   c) deposition of a metal by a chemical and/or electroplating method    on the at least partially dried and/or at least partially hardened    dispersion layer.

A suitable substrate is provided by electrically non-conductivematerials, such as polymers. Suitable polymers are epoxy resins, e.g.bifunctional or polyfunctional, aramid-reinforced or glassfiber-reinforced or paper-reinforced epoxy resins (e.g. FR4), glassfiber-reinforced plastics, liquid-crystal polymers (LCP), polyphenylenesulfides (PPS), polyoxymethylenes (POM), polyaryl ether ketones (PAEK),polyether ether ketones (PEEK), polyamides (PA), polycarbonates (PC),polybutylene terephthalates (PBT), polyethylene terephthalates (PET),polyimides (PI), polyimide resins, cyanate esters, bismaleimide-triazineresins, nylon, vinyl ester resins, polyesters, polyester resins,polyamides, polyanilines, phenolic resins, polypyrroles, polynaphthaleneterephthalates, polymethyl methacrylate, polyethylenedioxythiophenes,phenolic-resin-coated aramid paper, polytetrafluoroethylene (PTFE),melamine resins, silicone resins, fluoro resins, dielectrics, APPE,polyetherimides (PEI), polyphenylene oxides (PPO), polypropylenes (PP),polyethylenes (PE), polysulfones (PSU), polyether sulfones (PES),polyarylamides (PAA), polyvinyl chlorides (PVC), polystyrenes (PS),acrylonitrile-butadiene-styrenes (ABS), acrylonitrile-styrene-acrylates(ASA), styrene-acrylonitriles (SAN), and also mixtures (blends) of twoor more of the above-mentioned polymers, which may take a very widevariety of forms. The substrates can comprise additives known to theperson skilled in the art, e.g. flame retardants.

In principle, it is also possible to use any of the polymers listedunder component A′. Other suitable substrates are composite materials,foam-type polymers, Styropor® Styrodur®, polyurethanes (PU), ceramicsurfaces, textiles, cardboard, paperboard, paper, polymer-coated paper,wood, mineral materials, silicon, glass, plant tissue, or else animaltissue, or resin-saturated woven fabrics, pressed to give sheets orrolls.

For the purposes of this embodiment of the present invention, an“electrically non-conductive substrate” preferably means that thesurface resistance of the substrate is more than 10⁹ ohms/cm.

The dispersion can be applied to the substrate/backing by methods knownto the person skilled in the art.

Application to the substrate surface can take place on one or more sidesand can extend over one, two, or three dimensions. The substrate cangenerally have any desired geometry appropriate for the intendedpurpose.

The dispersion can be applied in structured or non-structured form instep a). It is preferable that the steps of application [step a)], ofdrying and/or hardening [step b)], and the deposition of a metal [stepc)] are carried out in a continuous procedure. This is possible byvirtue of the simple conduct of steps a), b), and c). However, abatchwise or semi-continuous process is, of course, possible.

The coating method used can involve the conventional and well-knowncoating processes (casting, spreading, doctoring, brushing, printing(intaglio print, screenprint, flexographic print, pad print, inkjet,offset, the LaserSonic® process, as described in DE10051850, etc.,spraying, dip-coating, rolling, powdering, fluidized bed, or the like).The layer thickness preferably varies from 0.01 to 100 μm, morepreferably from 0.1 to 50 μm, particularly preferably from 1 to 25 μm.The layers can be applied in a non-structured or structured manner.

Conventional methods are used for the drying or hardening of thedispersion applied in structured or non-structured form. For example,the dispersion can be hardened by a chemical route, e.g. via apolymerization, polyaddition or polycondensation reaction of the binder,for example via UV radiation, electron beam, microwave radiation, IRradiation, or heat, or by a purely physical route via evaporation of thesolvent. It is also possible to combine drying by a physical andchemical route.

The layer obtained after application of the dispersion and at leastpartial drying and/or at least partial hardening permits subsequentdeposition of a metal by a chemical and/or electroplating method on theat least partially dried and/or at least partially hardened dispersionlayer.

Metal Deposition on Substrate by an Electroplating Method

The substrates in whose surface carbon nanotubes are present, forexample the thermoplastic molding compositions comprising carbonnanotubes or the substrates coated with dispersions comprising carbonnanotubes, have particular suitability for deposition of metal layers byan electroplating method, i.e. for production of metallized substrates,without any need for complicated pretreatment of the substrate surface.

In principle, any of the processes known to the person skilled in theart and described in the literature for deposition of metals by anelectroplating method on plastic surfaces is suitable as process forproduction of the metallized substrates. (see, for example, HaroldEbneth et al., Metallisieren von Kunststoffen: Praktische Erfahrungenmit physikalisch, chemisch und galvanisch metallisierten Hochpolymeren[Metallization of plastics: practical experience with high polymersmetallized by physical, chemical, and electroplating methods], ExpertVerlag, Renningen-Malmsheim, 1995, ISBN 3-8169-1037-8; Kurt Heymann etal., Kunststoffinetallisierung: Handbuch für Theorie und Praxis[Metallization of plastics: theoretical and practical manual] No. 22 inthe series of publications entitled Galvanotechnik undOberflächenbehandlung [Electroplating technology and surface treatment],Saulgau: Leuze, 1991; Mittal, K. L. (ed.), Metallized Plastics ThreeFundamental and Applied Aspects, Third Electrochemical Society Symposiumon Metallized Plastics: Proceedings, Phoenix, Ariz., Oct. 13-18, 1991,New York, Plenum Press).

It is preferable that, after the respective final shaping process, themetallizable substrates are arranged as cathode via application of anelectrical potential and brought into contact with an acidic, neutral,or basic metal salt solution, whereupon the metal of this metal saltsolution is deposited by an electroplating method on the surfacecomprising the carbon nanotubes in the metallizable substrates.Preferred metals for deposition are chromium, nickel, copper, gold, andsilver, in particular copper. It is also possible to deposit a pluralityof metal layers in succession by an electroplating method, for exampleby introducing the metallizable substrates into dip-coating baths withsolutions of different metals, in each case with application of externalvoltage and flow of current.

Although no particular pretreatment of the surface of the metallizablesubstrates is needed prior to the metallization by a chemical and/orelectroplating method, it is possible in principle to carry out surfaceactivation by processes known to the person skilled in the art. Surfaceactivation of the substrate surface can be used to improve adhesion orelse to accelerate metal deposition, by roughening the surface in acontrolled manner or using a controlled method to release carbonnanotubes on the surface. Release of carbon nanotubes also has theadvantage that a smaller proportion is needed in the polymer matrix toachieve metallization.

By way of example, surface activation can take place via mechanicalabrasion, in particular via brushing, grinding, or polishing with anabrasive or impact under pressure from a water jet, sandblasting, orblasting with supercritical carbon dioxide (dry ice), or by physicalmethods, e.g. via heating, laser, UV light, corona or plasma discharge,and/or chemical abrasion, in particular via etching and/or oxidation.Processes for carrying out mechanical abrasion and/or chemical abrasionare known to the person skilled in the art and are described in theprior art.

The abrasive used for polishing can be any of the abrasives known to theperson skilled in the art. An example of a suitable abrasive is pumiceflour. In order to ablate the uppermost layer of the hardened dispersionwhen using a water jet under pressure, the water jet preferablycomprises small solid grains, such as pumice flour (Al₂O₃) whose averagegrain size distribution is from 40 to 120 μm, preferably from 60 to 80μm, or else powdered quartz (SiO₂) whose grain size is >3 μm.

Surface activation can also take place via stretching (also often termeddrawing or extending) of the metallizable substrate, in particular by afactor of from 1.1 to 10, preferably from 1.2 to 5, particularlypreferably from 1.3 to 3. The embodiments mentioned of mechanical and/orchemical abrasion and of stretching can, of course, also be applied incombination with one another for surface activation.

The stretching can take place in one or more directions. In the case ofextruded profiles, strands, or tubes, stretching preferably takes placein one direction, and in the case of sheet-like plastics articles it ispreferable that multidirectional, in particular bidirectional,stretching takes place, for example in the blow-molding or thermoformingprocess on foils or sheets. In the case of multidirectional stretching,it is essential that the stretching factor mentioned is achieved in atleast one direction of stretching. Processes that can be used forstretching are in principle any of the stretching processes described inthe literature and known to the person skilled in the art. Examples ofpreferred stretching processes for foils are blow-molding processes.

In the case of chemical abrasion, it is preferable to use a chemical ormixture of chemicals appropriate for the polymer of the substrate. Inthe case of chemical abrasion, the polymer can, for example, be at leastpartially dissolved away at the surface by a solvent, or the chemicalstructure of the matrix material can be at least to some extentdisrupted by means of suitable reagents, thus releasing the carbonnanotubes. Reagents which swell the matrix material are also suitablefor releasing the carbon nanotubes. The swelling produces cavities inwhich the metal ions to be deposited can penetrate from the electrolytesolution, thus permitting metallization of a greater number of carbonnanotubes. The greater number of released carbon nanotubes raises therate of the metallizing process.

If the matrix material is, for example, an epoxy resin, a modified epoxyresin, an epoxy-novolak, a polyacrylate, ABS, a styrene-butadienecopolymer, or a polyether, release of the carbon nanotubes is preferablyachieved by an oxidant. The oxidant breaks bonds of the matrix material,thus permitting break-away of the binder with resultant release of theparticles. Examples of suitable oxidants are manganates, e.g. potassiumpermanganate, potassium manganate, sodium permanganate, sodiummanganate, hydrogen peroxide, oxygen, oxygen in the presence ofcatalysts, e.g. salts of manganese, of molybdenum, of bismuth, oftungsten, and of cobalt, ozone, vanadium pentoxide, selenium dioxide,ammonium polysulfide solution, sulfur in the presence of ammonia or ofamines, manganese dioxide, potassium ferrate, dichromate/sulfuric acid,chromic acid in sulfuric acid or in acetic acid or in acetic anhydride,nitric acid, hydroiodic acid, hydrobromic acid, pyridinium dichromate,chromic acid-pyridine complex, chromic anhydride, chromium(VI) oxide,periodic acid, lead tetraacetate, quinone, methylquinone, anthraquinone,bromine, chlorine, fluorine, ferric salt solutions, disulfate solutions,sodium percarbonate, salts of oxohalic acids, e.g. chlorates or bromatesor iodates, salts of perhalo acids, e.g. sodium periodate or sodiumperchlorate, sodium perborate, dichromates, e.g. sodium dichromate,salts of persulfuric acid, such as potassium peroxodisulfate, potassiumperoxomonosulfate, pyridinium chlorochromate, salts of hypohalic acids,e.g. sodium hypochloride, dimethyl sulfoxide in the presence ofelectrophilic reagents, tert-butyl hydroperoxide, 3-chloroperbenzoicacid, 2,2-dimethylpropanal, Des-Martin-periodinane, oxalyl chloride,urea-hydrogen peroxide adduct, urea peroxide, 2-iodoxybenzoic acid,potassium peroxomonosulfate, m-chloroperbenzoic acid, N-methylmorpholineN-oxide, 2-methylprop-2-yl hydroperoxide, peracetic acid, pivaldehyde,osmium tetraoxide, oxones, ruthenium(III) salts and ruthenium(IV) salts,oxygen in the presence 2,2,6,6-tetramethylpiperidinyl N-oxide,triacetoxyperiodinane, trifluoroperacetic acid, trimethylacetaldehyde,ammonium nitrate. The temperature can optionally be increased during theprocess in order to improve the release process.

Preference is given to manganates, such as potassium permanganate,potassium manganate, sodium permanganate; sodium manganate, hydrogenperoxide, N-methyl-morpholine N-oxide, percarbonates, e.g. sodiumpercarbonate or potassium percarbonate, perborates, e.g. sodiumperborate or potassium perborate; persulfates, such as sodium persulfateor potassium persulfate; the peroxodi- and -monosulfates of sodium, ofpotassium, and of ammonium, sodium hypochloride, urea-hydrogen peroxideadducts, salts of oxohalic acids, such as chlorates or bromates oriodates, salts of perhalic acids, such as sodium periodate or sodiumperchlorate, tetrabutylammonium peroxydisulfate, quinones, ferric saltsolutions, vanadium pentoxide, pyridinium dichromate, hydrochloric acid,bromine, chlorine, dichromates.

Particular preference is given to potassium permanganate, potassiummanganate, sodium permanganate, sodium manganate, hydrogen peroxide andits adducts, perborates, percarbonates, persulfates, peroxodisulfates,sodium hypochloride, and perchlorates.

For release of the carbon nanotubes in a matrix material whichcomprises, for example, ester structures, e.g. polyester resins,polyester acrylates, polyether acrylates, polyester urethanes, it ispreferable to use, for example, acidic or alkaline chemicals and/ormixtures of chemicals. Preferred acidic chemicals and/or mixtures ofchemicals are, for example, concentrated or dilute acids, such ashydrochloric acid, sulfuric acid, phosphoric acid, or nitric acid.Organic acids can also be suitable as a function of the matrix material,examples being formic acid or acetic acid. Suitable alkaline chemicalsand/or mixtures of chemicals are, for example, bases, such as sodiumhydroxide solution, potassium hydroxide solution, ammonium hydroxide, orcarbonates, such as sodium carbonate or potassium carbonate. Thetemperature can optionally be increased during the process in order toimprove the release process.

Solvents can also be used for release of the carbon nanotubes in thematrix material. The solvent has to be appropriately matched to thematrix material, since the matrix material must undergo dissolution inthe solvent or solvation by the solvent. If a solvent in which thematrix material is soluble is used, the base layer is brought intocontact with the solvent for only a short time, in order that the upperlayer of the matrix material is solvated and thus separated. Inprinciple, any of the abovementioned solvents can be used. Preferredsolvents are xylene, toluene, halogenated hydrocarbons, acetone, methylethyl ketone (MEK), methyl isobutyl ketone (MIBK), diethylene glycolmonobutyl ether. To improve solvent behavior, the temperature canoptionally be increased during the dissolution procedure.

The thicknesses of the one or more metal layers deposited by a chemicaland/or electroplating method are within the conventional range known tothe person skilled in the art and are not significant for the invention.

Particularly preferred metallized substrates for use as electricallyconducting components, in particular printed circuit boards, have atleast one metal layer deposited by a chemical and/or electroplatingmethod, in particular a copper layer, silver layer, or gold layer.

Particularly preferred metallized substrates for use in the decorativesector have a copper layer deposited by a chemical and/or electroplatingmethod, and a nickel layer thereupon deposited by a chemical and/orelectroplating method, and a chromium layer, silver layer, or gold layerdeposited thereupon.

The metallized substrates, if appropriate after production of conductortrack structures by the processes described in the literature and knownto the person skilled in the art, are suitable as electricallyconducting components, in particular printed circuit boards, RFIDantennas, transponder antennas, or other antenna structures, switches,sensors, and MIDs, EMI shielding materials (i.e. shielding to avoidelectromagnetic interference), such as absorbers, attenuators, orreflectors for electromagnetic radiation, or as gas barriers ordecorative parts, in particular decorative parts in the motor vehiclesector, sanitary sector, toy sector, household sector, and officesector.

Examples of these applications are: computer cases, cases for electroniccomponents, military and non-military shielding, devices, shaverfittings and washstand fittings, shower heads, shower rails, showerholders, metallized door handles and door knobs, toilet-paper-rollholders, bathtub grips, metallized decorative strips on furniture and onmirrors, and frames for shower partitions.

Mention may also be made of: metallized plastics surfaces in theautomotive sector, e.g. decorative strips, exterior mirrors, radiatorgrilles, front end metallization, aerofoil surfaces, exterior bodyworkparts, door sills, replacement tread plate, decorative wheel covers.

Parts that can be produced from plastic are particularly those whichhitherto have been produced partially or entirely from metals. Examplesthat may be mentioned here are: tools, such as pliers, screwdrivers,drills, drill chucks, saw blades, ring wrenches, and open-jaw wrenches.

The metallized substrates—insofar as they comprise magnetizablemetals—are also used in the sectors of magnetizable functional parts,e.g. magnetic panels, magnetic games, magnetic surfaces in, for example,refrigerator doors. They are also applied in sectors where good thermalconductivity is advantageous, for example in foils for seat-heatingsystems, floor covering-heating systems, insulation materials.

The inventive processes permit improved application of a metal layer ona substrate via deposition of a metal from a metal salt solution by achemical and/or electroplating method. In particular, the inventiveprocesses can deposit, on a substrate, metal layers with good adhesionto the substrate within comparatively short electroplating times at lowcost and with good quality. The resultant metallized substrates havecomparatively low weight.

Examples are used below for further illustration of the invention.

EXAMPLES Experimental part 1 Substrates Composed of a MoldingComposition Comprising Carbon Nanotubes

The following were used as component A:

-   A-i Styroflex® 2G66, an S-TPE from BASF Aktiengesellschaft.-   A-ii PP4821 polypropylene from Borealis, melt flow index 2.4 g/10    min (determined to ISO 1133 at 230° C. and 2.16 kg).

The following were used as component B:

-   B-i Baytubes® C150P, multiwall carbon nanotubes from Bayer Material    Science AG with carbon content >95% by weight, with average particle    diameter of from 13 to 16 nm and with length of from 1 to 10 μm.

The following components were used for non-inventive comparativeexperiments:

-   Comp-i: Vulcan® XC 72R, conductive carbon black from Cabot Corp.

Production of Metallizable Substrates:

Taking the quantitative proportions of component A mentioned in Table 1,in an IKA Duplex kneader at temperatures of from 120° C. to 150° C., thequantitative proportions likewise mentioned in Table 1 of the furthercomponents were added in portions and mixed (data in % by weight, basedin each case on the total weight of all of the components). The moldingcompositions obtained after kneading for about 30 minutes wereinjection-molded to give flat test specimens of edge length 50×50 mm.

Surface Activation:

The following surface activation was also carried out on theappropriately indicated test specimens in Table 1:

The test specimens were immersed for a period of 2 min in an aqueoussolution whose temperature was 80° C. comprising 6% by weight of KMnO₄and 4.5% by weight of NaOH (based in each case on the total weight ofthe aqueous solution). The test specimens were then rinsed with a streamof running water for 30 s. Finally, the test specimens were immersed fora period of 1 min in an aqueous solution comprising 2% by weight of H₂O₂and 10% by weight of H₂SO₄ (based in each case on the total weight ofthe aqueous solution).

Metallization:

The test specimens were metallized for a period of 30 min via immersionand application of an electrical potential of 1 V into a commerciallyavailable acidic Cupracid® HS copper sulfate bath (comprising 21% byweight of CuSO₄, 5.5% by weight of H₂SO₄, 0.2% by weight of brightener,0.5% by weight of HS leveler, and 0.02% by weight of NaCl, based in eachcase on the total weight of the solution, in aqueous solution) fromAtotech. A test specimen was regarded as metallizable if a visuallyhomogeneous copper layer had deposited on the entire test specimen afterthe minutes of electroplating.

Table 1 gives the metallizability of the test specimens.

TABLE 1 Constitution of molding compositions [% by weight, based ontotal weight Example* of molding compositions] 1 2 3 Comp-1 Comp-2 A-i80 92 — 80 80 A-ii — — 90 — — B-i 20 8 10 — 10 Comp-i — — — 20 10Surface activation no yes yes no no Metallizability** yes yes yes no no*examples indicated by “comp” are comparative examples, **a testspecimen was classified with “yes” for metallizability if a visuallyhomogeneous copper layer had deposited on the entire test specimen afterthe 30 minutes of electroplating mentioned in the description.

Experimental part 2 Coating of a Substrate with a Dispersion ComprisingCarbon Nanotubes

The following were used as component A′:

-   A′-i Styroflex® 2G66, an S-TPE from BASF Aktiengesellschaft.

The following were used as component B′:

-   B′-i Baytubes® C150P, multiwall carbon nanotubes from Bayer Material    Science AG with carbon content >95% by weight, with average particle    diameter of from 13 to 16 nm and with length of from 1 to 10 μm.

The following were used as component C′:

-   C′-i n-butyl acetate.

The following were used as component E′:

-   E′-i: Vulcan® XC 72R, a conductive carbon black from Cabot Corp.

Preparation of Dispersions:

Taking the quantitative proportions mentioned in Table 2 of componentA′, the quantitative proportions of component B′ likewise mentioned inTable 2 were added in portions and mixed in an IKA Duplex kneader attemperatures of 120° C. (data in % by weight, based in each case on thetotal weight of all of the components).

The resultant mixtures were mixed in a Skandex DAS 200 mixer for aperiod of 1 h in the presence of glass particles with the quantitativeproportions mentioned in Table 2 of component C′ and, if appropriate, offurther components (data in % by weight, based in each case on the totalweight of all of the components). The glass particles were then removed.

Coating of Substrate:

The resultant dispersions were further processed by two alternativemethods (indicated in Table 2):

-   α) the dispersions were applied to a foil composed of polyethylene    terephthalate as substrate. Ten minutes of drying of the dispersion    at 80° C. followed, with formation of a layer of thickness about 25    μm on the substrate; or-   β) the dispersions were printed by means of a Saueressig CP90/200    gravure color proofer in the form of an RFID antenna onto a foil    composed of polyethylene terephthalate as substrate, and then dried    to form tracks whose layer thickness was about 3 μm.

Surface Activation:

In the case of coated substrates appropriately indicated in Table 2, thefollowing surface activation was also carried out:

The coated substrates were immersed for a period of 2 min in an aqueoussolution whose temperature was 80° C. comprising 6% by weight of KMnO₄and 4.5% by weight of NaOH (based in each case on the total weight ofthe aqueous solution). The coated substrates were then rinsed with astream of running water for 30 s. Finally, the coated substrates wereimmersed for a period of 1 min in an aqueous solution comprising 2% byweight of H₂O₂ and 10% by weight of H₂SO₄ (based in each case on thetotal weight of the aqueous solution).

Metallization:

The coated substrates were metallized for a period of 30 min viaimmersion and application of an electrical potential of 1 V into acommercially available acidic Cupracid® HS copper sulfate bath(comprising 21% by weight of CuSO₄, 5.5% by weight of H₂SO₄, 0.2% byweight of brightener, 0.5% by weight of HS leveler, and 0.02% by weightof NaCl, based in each case on the total weight of the solution, inaqueous solution) from Atotech. A coated substrate was regarded asmetallizable if a visually homogeneous copper layer had deposited on theentire substrate after the 30 minutes of electroplating.

Table 2 gives the metallizability of the coated substrates.

TABLE 2 Example* 1 2 Constitution of dispersion [% by weight, based ontotal weight of dispersion] A′-i 22 12.2 B′-i 3 1.7 C′-i 75 83.3 E′-i —2.8 Method of further processing α β Surface activation yes yesMetallizability* yes yes *a coated substrate was classified with “yes”for metallizability if a visually homogeneous copper layer had depositedon the entire substrate after the 30 minutes of electroplating mentionedin the description.

1. A process for application of a metal layer on a substrate viadeposition of a metal from a metal salt solution, which comprises thepresence of carbon nanotubes in the substrate surface.
 2. The processaccording to claim 1, wherein the carbon nanotubes used comprise single-or multiwall carbon nanotubes whose length is in the range from 0.5 to1000 μm and whose diameter is in the range from 0.002 to 0.5 μm.
 3. Theprocess according to claim 1, wherein the substrate comprises athermoplastic molding composition, where the thermoplastic moldingcomposition comprises, based on the total weight of components A, B, C,and D, which is 100% by weight, a from 20 to 99% by weight of athermoplastic polymer, as component A, b from 1 to 30% by weight ofcarbon nanotubes, as component B, c from 0 to 10% by weight of adispersing agent, as component C, and d from 0 to 40% by weight offibrous or particulate fillers, or a mixture of these, as component D.4. The process according to claim 3, wherein the component A usedcomprises one or more polymers selected from the group ofimpact-modified vinylaromatic copolymers, polyolefins, polycarbonates,thermoplastic polyurethanes, and styrene-based thermoplastic elastomers.5. The process according to claim 1, wherein the substrate is providedwith a dispersion, and the dispersion is at least partially dried and/orat least partially hardened and, after the at least partial dryingand/or at least partial hardening of the dispersion, deposition of themetal takes place by a chemical and/or electroplating method, where thedispersion comprises a′ from 0.1 to 99.9% by weight, based on the totalweight of components A′, B′, and C′, of an organic binder component A′;b′ from 0.1 to 30% by weight, based on the total weight of componentsA′, B′, and C′, of carbon nanotubes, as component B′; c′ from 0 to 99.8%by weight, based on the total weight of components A′, B′, and C′, of asolvent component C′.
 6. The process according to claim 5, wherein thedispersion moreover comprises at least one of the following components:d′ from 0.1 to 50% by weight, based on the total weight of componentsA′, B′, and C′, of a dispersing agent component D′; and also e′ from 0.1to 50% by weight, based on the total weight of components A′, B′, andC′, of a filler component E′.
 7. The process according to claim 5,wherein the binder component A′ is composed of a polymer or polymermixture.
 8. The process according to claim 5, wherein the dispersion isapplied in structured or non-structured form to the substrate.
 9. Theprocess according to claim 1, wherein the substrate surface in whichcarbon nanotubes are present is activated prior to deposition of a metalby a chemical and/or electroplating method.
 10. (canceled)
 11. Asubstrate surface at least partially having an electrically conductivemetal layer obtainable from the process according to claim
 1. 12. Thesubstrate surface according to claim 11 wherein the electricallyconductive metal layer is provided for conducting electrical current orheat, or as a decorative metal surface, or for shielding fromelectromagnetic radiation, or else for magnetizing.
 13. A printedcircuit board, RFID antenna, transponder antenna or other antennastructure, seat-heating system, ribbon cable, foil conductor,contactless chip card, conductor tracks in solar cells, or in LCDdisplay screens or in plasma display screens comprising the substratesurface according to claim
 12. 14. The process according to claim 2,wherein the substrate comprises a thermoplastic molding composition,where the thermoplastic molding composition comprises, based on thetotal weight of components A, B, C, and D, which is 100% by weight, afrom 20 to 99% by weight of a thermoplastic polymer, as component A, bfrom 1 to 30% by weight of carbon nanotubes, as component B, c from 0 to10% by weight of a dispersing agent, as component C, and d from 0 to 40%by weight of fibrous or particulate fillers, or a mixture of these, ascomponent D.
 15. The process according to claim 2, wherein the substrateis provided with a dispersion, and the dispersion is at least partiallydried and/or at least partially hardened and, after the at least partialdrying and/or at least partial hardening of the dispersion, depositionof the metal takes place by a chemical and/or electroplating method,where the dispersion comprises a′ from 0.1 to 99.9% by weight, based onthe total weight of components A′, B′, and C′, of an organic bindercomponent A′; b′ from 0.1 to 30% by weight, based on the total weight ofcomponents A′, B′, and C′, of carbon nanotubes, as component B′; c′ from0 to 99.8% by weight, based on the total weight of components A′, B′,and C′, of a solvent component C′.
 16. The process according to claim 6,wherein the binder component A′ is composed of a polymer or polymermixture.
 17. The process according to claim 6, wherein the dispersion isapplied in structured or non-structured form to the substrate.
 18. Theprocess according to claim 7, wherein the dispersion is applied instructured or non-structured form to the substrate.
 19. The processaccording to claim 2, wherein the substrate surface in which carbonnanotubes are present is activated prior to deposition of a metal by achemical and/or electroplating method.
 20. The process according toclaim 3, wherein the substrate surface in which carbon nanotubes arepresent is activated prior to deposition of a metal by a chemical and/orelectroplating method.
 21. The process according to claim 4, wherein thesubstrate surface in which carbon nanotubes are present is activatedprior to deposition of a metal by a chemical and/or electroplatingmethod.